Smoking and Your Lungs: Which Diseases to Know

Smoking is the main cause of the chronic lung diseases Canadians hear about most: COPD, which includes emphysema and chronic bronchitis, and lung cancer. The Public Health Agency of Canada says cigarette smoking is the principal cause in 80% to 90% of COPD cases. This page maps each condition and links to the detail guides.

The main conditions at a glance

Condition	What it is	Read more
COPD	A long-term disease that limits airflow and worsens slowly. Health Canada says it includes chronic bronchitis and emphysema.	COPD symptoms and COPD stages
Emphysema	Damage to the air sacs in the lungs. One of the two conditions that make up COPD.	Emphysema
Chronic bronchitis	Long-lasting inflammation of the airways with a cough and phlegm. The other condition under COPD.	Chronic bronchitis
Lung cancer	Cancer that starts in the lungs. Health Canada says smoking accounts for 85% of all new cases in Canada.	Lung cancer symptoms and smoking and cancer

Health Canada also says that a person diagnosed with emphysema or chronic bronchitis is considered to have COPD, so the names often describe the same overall illness.

Which page should I read?

• You want to see what smoke does to airways and tissue: smoker’s lungs compared with healthy lungs.
• You have a cough that will not go away: smoker’s cough, causes and when to see a doctor.
• You have been told you may have COPD, or want to know how it is graded: COPD stages and smoking.
• You are unsure how much you have smoked: use the pack-year calculator, then the lung screening eligibility checker to see whether you may qualify to ask about screening.
• You vape or are thinking about it: e-cigarette risks and benefits summarizes what Health Canada says.

Symptoms overlap between these conditions. A long cough, breathlessness or blood in the phlegm needs a clinician, not a web page. Call 811 where it is available, or 9-1-1 in an emergency.

What quitting changes

Quitting does not reverse everything, and emphysema damage is permanent. Even so, Health Canada describes quitting as the most effective way to stop further lung damage, and the airways start to relax within weeks to months. Our guide to how lungs recover after quitting lays out the timeline.

When you are ready to stop, the quit smoking hub covers methods and medications, and free quit-smoking help by province shows what your province offers.

What we could not confirm

We did not find an official Canadian page we could open that gives a current count of Canadians living with COPD or dying of lung cancer, so we do not state one. Official figures for smoking’s share of lung cancer differ between Health Canada pages, so we quote one source and name it. This page is general information, not a diagnosis. Only a clinician can tell you what is going on in your lungs.